This invention relates to a curable resin composition comprising a mixture and/or a preliminary reaction product of (a) a polyfunctional cyanate ester, prepolymer of the cyanate ester or coprepolymer of the cyanate ester and an amine (sometimes hereunder referred to as component (a)), and (b) cyclopentadiene or polycyclopentadiene (sometimes hereinunder referred to as component (b)) and also relates to a curable resin composition comprising a mixture and/or a preliminary reaction product of (a) a polyfunctional cyanate ester, prepolymer of the cyanate ester or coprepolymer of the cyanate ester and an amine, (b) cyclopentadiene or polycyclopentadiene and (c) a polyfunctional maleimide, prepolymer of the maleimide or coprepolymer of the maleimide and an amine (sometimes hereinunder referred to as component (c)). Cured resin obtained by curing each of the resin compositions has excellent impact-resistance, adhesive, power, heat-resistance and chemical resistance.
In the prior art, the cured resin obtained by cast-molding a composition containing a polyfunctional maleimide and a polyfunctional cyanate ester has low impact resistance. Similarly, the cured resin obtained by cast-molding cyclopentadiene resin is fragile.